Electronic integrating meter

Abstract

An electronic integrating meter comprises a rotatable body having a magnet attached thereto and rotatable in proportion to a quantity to be measured, a magneto-resistive element having a pair of resistances variable responsive to the magnetic field generated as the magnet varies in position upon rotation of said rotatable body, a circuit for generating first clock pulses during intervals of time alternately variable based on two time constants determined by said resistances each time a second clock signal is applied, a device for producing a switching control signal from the second clock signal, and a counter responsive to said switching control signal for counting the first clock pulses during the alternate periods of time determined by the two time constants and for producing the difference between the resulting counts, a flip-flop for producing an output each time the excess between counts switches from one train to the other and logic apparatus for weighting the output of the flip-flop.

What is claimed is: 
     
       1. An electronic integrating meter comprising: a. a rotatable body;   b. a magnet attached to said body to rotate therewith;   c. a magneto-resistive element having at least first and second resistances, the values of which vary in response to rotation of said magnet;   d. a means for developing first clock pulses;   e. circuit means, coupled to said resistances and having first and second time constants which vary as a function of said first and second resistances, respectively, for developing first and second pulses at predetermined time intervals which each include a variable number of said first clock pulses in the form of a pulse train, each of said variable numbers of said first clock pulses being representative of a respective one of said first and second time constants during a selected one of said predetermined time intervals;   f. means for determining which of successive first and second pulses has the greater number of said first clock pulses; and   g. means, responsive to said means for determining, for indicating the occurrence of a revolution of said body.   
     
     
       2. An electronic integrating meter comprising: a. a rotatable body;   b. a magnet attached to said body to rotate therewith;   c. a magneto-resistive element having at least first and second resistances, the values of which vary in response to rotation of said magnet;   d. a means for developing first clock pulses;   e. circuit means, coupled to said resistances and having first and second time constants which vary as a function of said first and second resistances, respectively, for developing first and second pulses each beginning at regular intervals, said first and second pulses having variable lengths which correspond to said first and second time constants, respectively;   f. means for selecting for each first and second pulse a number of said first clock pulses corresponding to be length of each said first and second pulse;   g. means for determining which of first and second pulses, for selected ones of said regular intervals, has the greater number of said first clock pulses; and   h. means, responsive to said means for determining, for indicating the occurrence of a revolution of said body.   
     
     
       3. The electronic integrating meter of claim 1 or 2 including means for weighting, by a selected factor, the output of said means for indicating the occurrence of a revolution of said body. 
     
     
       4. The electronic integrating meter of claim 3 wherein said means for weighting includes means for adjusting said factor. 
     
     
       5. An electronic integrating meter comprising: a. a rotatable body;   b. a magnet attached to said body to rotate therewith;   c. a magneto-resistive element having at least first and second resistances, the values of which vary in response to rotation of said magnet;   d. a means for developing first clock pulses;   e. circuit means, coupled to said resistances and having first and second time constants which vary as a function of said first and second resistances, respectively, for developing first and second pulses each beginning at regular intervals, said first and second pulses having variable lengths which correspond to said first and second time constants, respectively;   f. means for selecting for each first and second pulse a number of said first clock pulses corresponding to the length of each said first and second pulse;   g. means for determining which of first and second pulses, for selected ones of said regular intervals, has the greater number of said first clock pulses;   h. means, responsive to said means for determining, for indicating the occurrence of a revolution of said body;   i. means for producing a selected number of second clock pulses; and   j. a rate multiplier including means for storing said selected number of second clock pulses, said rate multiplier being coupled to receive an output signal from said means for indicating the occurrence of a revolution of said body and said rate meter being operable to weight said output signal in response to said stored selected number of second clock pulses, whereby said rate multiplier provides a weighted indication of the number of revolutions of said body.   
     
     
       6. The electronic integrating meter of claims 1, 2 or 5 wherein said means for determining provides an output signal which indicates when said greater number of said first clock pulses in successive first and second pulses shifts from one to the other of said first and second pulses. 
     
     
       7. The electronic integrating meter of claim 6 wherein said circuit means for developing first and second pulses includes a monostable multivibrator alternately responsive to said first and second time constants during successive ones of said time intervals. 
     
     
       8. The electronic integrating meter of claim 6 wherein said means for determining includes first and second counters for counting said first clock pulses in said first and second pulses, respectively, for each successive one of said time intervals, and a comparator which produces said output signal of said means for determining when said greater number of said first clock pulses in successive first and second pulses shifts from one to the other of said first and second pulses. 
     
     
       9. The electronic integrating meter of claim 6 wherein said means for determining includes an up-down counter for adding said first clock pulses in said first pulses and for subtracting therefrom said first clock pulses in said second pulses and which, in response to said adding and subtracting, produces a change in said output signal of said means for determining when said greater number of said first clock pulses in successive first and second pulses shifts from one to the other of said first and second pulses. 
     
     
       10. The electronic integrating meter of claim 6 wherein said means for indicating the occurrence of a revolution of said body comprises a flip-flop connected to the output of said means for determining.